Objectives: To systematically review the efficacy of misoprostol compared with placebo or other uterotonics in preventing maternal morbidity associated with the third stage of labor. Methods: We identified, retrieved, evaluated, abstracted data, and assessed the quality of all published studies (from January 1996 to May 2002) which assessed misoprostol's efficacy in minimizing uterine blood loss during the third stage of labor. Seventeen studies included 28 170 subjects; of these, approximately one-half received misoprostol with the remainder receiving either a placebo or another uterotonic agent. An estimate of the odds ratio (OR) and risk difference for dichotomous outcomes was calculated using a random- and fixed-effects model. Continuous outcomes were pooled using a variance-weighted average of within-study difference in means. Results: In assessing studies comparing misoprostol with placebo, those who received oral misoprostol had a decreased risk of needing additional uterotonics (OR 0.64, 95% confidence interval 0.46, 0.90). Compared with placebo, use of misoprostol was associated with an increased risk for shivering and pyrexia. In contrast, in studies comparing misoprostol with oxytocin, oxytocin was associated with significantly lower rates of postpartum hemorrhage, maternal shivering and pyrexia. In studies comparing misoprostol with Syntometrine, misoprostol was associated with higher rates of the need for additional uterotonic agent as well as shivering. Conclusions: Misoprostol was inferior to oxytocin and other uterotonics with regard to any of the third stage of labor outcomes assessed. However, when compared to placebo, misoprostol had a decreased risk of needing additional uterotonics. Thus, in less-developed countries where administration of parenteral uterotonic drugs may be problematic, misoprostol represents a reasonable agent for the management of the third stage of labor. Additional randomized clinical trials examining objective outcome measures (i.e. need for blood transfusion or 10% hemoglobin change) may further define benefits and risks of misoprostol use during the third stage of labor. (C) 2003 International Federation of Gynecology and Obstetrics. Published by Elsevier Science Ireland Ltd. All rights reserved.